Introduction: Combination Ergonomic Frame Pack, PVC Take-down Recurve Bow, and Hammock
Third Prize in the
Apocalypse Preparedness Contest
I don't know about you, but when the apocalypse hits I am unlikely to be in a bunker stocked with food, weapons, and entertainment. So I will have to travel to get to that bunker. Probably a very long way. I also don't want to carry a lot of extra gear. I want all my gear to serve multiple purposes so I can travel light while maintaining versatility. Lastly, I am unlikely to be prepared for this event (hence my absence from the well-stocked bunker), and so I will probably have to find/scavenge all my gear.
To solve many of these problems I give you the VersaBow. This take-down recurve bow can easily be deconstructed and combined with a simple hammock (also a very versatile item) to form an ergonomic frame backpack. It also can be constructed from 100% easily scavengeable materials and tools with or without the aid of electricity. Truly, this is a device that covers all your apocalypse needs.
Before we get started I'd just like to give a shout out to Nick
Tomihama, The Backyard Bowyer. This bow is primarily inspired by his work. If this bow isn't to your style he's got a lot more on his youtube channel and his books. They're definitely worth a look.
Step 1: Tools and Materials
Materials for bow:
5ft. of 1in. schedule 40 PVC pipe (I like to have a little extra around for the inevitable screw-up)
2ft. of 3/4in. schedule 40 PVC pipe
Large board at least 3ft. long
Things to know when acquiring PVC :
PVC pipe will degrade when exposed to UV light. For this reason it is usually a bad idea to store it outside for prolonged periods of time. You should also avoid using PVC that is yellow or brown because that is an indication that it has been sitting in the sun for too long.
PVC pipe comes in two varieties, white and gray. Gray PVC is used as electrical conduit. White is used for plumbing. Either one will make a fine bow and there will be very little difference between them. In general white PVC will have a little more snap than gray, and gray will be somewhat more resistant to UV light than white (you should probably add a coat of spray paint anyway). I chose gray PVC because I find it is easier to shave and file down.
NOTE: PVC pipe comes in these varieties in the U.S. In other countries gray and white may be used for different things and be color coded differently.
PVC schedule refers to the width of the pipe wall. You can usually find schedule 40 and schedule 80 at hardware stores. I will be using schedule 40 for this project, but if you prefer bows with higher draw weights than this one, switching to schedule 80 is one of the ways you can accomplish this (changing the length or additonal recurve can also affect the draw weight of your bow but we'll talk about that later).
Materials for Hammock:
Double sized bedsheet
20ft. of rope
Materials for Pack:
Leather laces (or some other lashing material)
Heat gun (a propane torch, gas stove top, or even a good bed of coals would also work)
Work gloves (in order to shape the pipe we need to work with it when it's VERY hot)
Step 2: Bow Terminology
Here are some terms I'm going to use during this instructable. Experienced bowyers (people who make bows)
and archery buffs will undoubtedly know these already but the new guys probably won't and it will be easier on all of us if we speak the same language.
"Siyah" or "Bow-ear"- the rigid, forward curving tip of a recurve bow.
Siyah shape is an important part of recurve construction. The siyahs themselves don't flex and so don't add anything to the draw weight of the bow, but when the bowstring is released they act as levers and snap the string forward faster than it would otherwise go. Because of this they don't need to be made from as heavy a material as the rest of the bow, in fact it helps if they are lighter which is why I used a smaller pipe for this project.
"Bow arm"- The section of the bow from the handle to the tips.
"Nock"- The groove at the tip of the bow where the bowstring rests
"Back"- the side of the bow that is farthest from the arc.her
"Belly"-the side of the bow that is closest to the archer.
"Weight" or "Draw weight"- how much the bow pulls against you when you draw it.
"Recurve"- a curve that curves away from the archer (will increase draw weight)
"Decurve"- a curve that curves owards the archer (will reduce draw weight)
"Brace"- the distance between the string
Step 3: Cutting and Marking Your PVC
First we need to cut the PVC into the sizes we're working with. You will need one 4ft. section (this will form the main body of the bow) and two 4in. sections (these will form the connections) from the one inch pipe and two 1ft. sections from the 3/4in. pipe (these will form the siyahs or bow-ears). Set aside the 4in.pieces for now.
After cutting your pieces mark the 4ft. section at the 2ft. mark, 3in. on either side of it, and 2in. from each end. I also like to mark 1ft. from each end as a reference. Then mark 2in. from one end on both of your 1ft. pieces. Mark the entire way around the pipe. This will become useful later. Remember to measure from a factory made edge whenever possible.
Step 4: Shaping the PVC: Initial Heating
WARNING! Only heat PVC pipe in a well ventilated area. Hot PVC pipe can give off fumes that are harmful when inhaled.
SECOND WARNING! PVC pipe has to be very hot before it becomes flexible enough to shape and has to be held in that shape as it cools. Heavy gloves are recommended.
First make a heating jig. You can do this by setting a board on the ground and setting a piece of aluminum foil in the corner between it and the ground. Set the pipe on top of it and you're ready to go. (Making a heating jig is completely optional but it makes the next part much easier)
Next take the 4ft. section of pipe and slowly start heating from the end to the edge of the handle marks. You'll know when it's hot enough because the pipe will become easily deformable.
Don't spend too much time on one spot or you'll end up burning the PVC.
PVC cools off much faster than is convenient. I like to heat 1ft. sections at a time (hence the extra marks I made) and fold the extra aluminum foil over them to hold the heat while I work on another section.
Step 5: Shaping the PVC: Tapering the Pipe
Place the pipe on the ground as straight as possible and place two spacers next to the handle marks. (I like to use extra scraps of pipe because they're already the right height.) Then place the board on top of the pipe and stand, kneel, or otherwise compress it so the pipe ends up round near the handle and completely flat at the tips.
After it cools take it out and check it for straightness. A little bit off is nothing to worry about but if it's off by too much reheat it and try again.
Now take the 1ft. sections of 3/4in. pipe and taper them the same way you did the 4ft. section. This time set the spacers at the 2in. mark you made before.
Step 6: Shaping the Siyahs
Measure 3/4in. from the side of the siyah and 1 3/4in. from the top. Draw a line between the two marks and cut along the line.
Now we have to give the siyah its characteristic curve. Take the siyah and heat up what will become the forward facing edge (the tallest edge). Try to heat it up slowly. It doesn't need to be as soft as when we tapered it. It just needs to be soft enough to flex forward in a gentle, banana-like curve. The siyah will puff out some from the flexing and heating but try to keep as much of the taper as possible. As always, if you mess up too bad, you can always reheat the piece and try again.
(Sorry I don't have any pictures of the process. My assistant had better things to do and I only have two hands)
Next add the string nocks by drilling 3/16in. hole through the tip (In the spirit of the apocalypse I drilled the hole by hand). I made mine 1/2in. from the top and 3/8in. from the front. Then take a hacksaw and cut to the hole at an angle. Shave the sharp edges off the cuts and drill hole using a knife or file so that they don't cut the bowstring when you string it.
Repeat for the other 1ft. section of pipe.
Step 7: Attaching the Siyahs
Take the 4ft. section of pipe and heat up the last two inches (remember that mark we made at the very beginning)
plus a little extra. Heat it until it puffs back out to a round cross section. Now push your newly shaped siyah up to the two inch mark into this puffed out section. Make sure the siyahs are facing the right direction. If the bow is laying flat on the ground the siyahs should point straight up. Once they're in, bend them slightly forward so that there is a nice transition between the belly of the bow and the bulge where the siyah comes in. Sight down the bow to make sure the siyahs line up with the mid-line and adjust if necessary.
Repeat for the other end.
Step 8: Adding Curves
Take your bow and slowly heat up the section between the handle and the siyah. Once again your goal is to heat slowly and evenly. The PVC doesn't need to be very soft. It just needs to be soft enough that you can put a curve in it. Curve the bow so that if you were holding it vertically the tip would point straight up. Let it cool against a flat surface like the floor so that the bow stays straight and doesn't twist (The amount of curve you put in the handle is a large factor in the draw weight of the bow. The farther backward it's bent the lighter the draw weight).
Repeat for the other end. When trying to match the curves I find it helpful to set the bow against something straight to compare both sides.
Be careful when heating tapered PVC. If you heat the edge too quickly without heating the flat part it will sometimes split and ruin all the work you've done so far.
Step 9: Making the Handle
To make the handle heat up that 6in. section in the middle of the bow that we've been ignoring thus far. Once it becomes flexible enough to squeeze with one hand grab each side of bow and bend it so the tips of the bow face forward. (The amount of curve you put in the handle is a large factor in the draw weight of the bow. The farther forward it's bent the heavier the draw weight)
After a time the handle will cool enough that it is unlikely to lose the shape you gave it, but it is still flexible enough to mold. When this happens squeeze the handle so that the cross sections changes from a circle to an oval with the longest diameter line pointing the same direction as the siyahs. Once again sight down the bow to make sure it's still straight and adjust if necessary.
Now is a good time to check the curves you put in it. This bow will eventually pop apart into three pieces to form the frame for a pack, so it is important that the curves fit your back. Check the handle section against your lower back and the arms of the bow against your upper back slanting from the shoulders to the ribs. If the curves of the bow don't match the curves of your back it's probably a good idea to adjust them.
Step 10: Optional Arrow Rest
I prefer bows without arrow rests but many people do not share this opinion. If you are one these people a simple tab style arrow rest can be added very easily. Take a piece of scrap pipe and cut a small piece about 2in. long. Shave or file the sharp edges off of it until one end is narrower than the other. Test it against the side of the handle. Does it more or less fit against the side? Make whatever adjustments are needed so that it does. Next heat up the last 1/2in. of the wider end and bend it at a 90 degree angle. Glue it on the side of the handle using PVC cement.
Step 11: Cutting the Bow Apart
At this point you should have a beautifully shaped, fully functional bow that you made over the course of an hour or two. You can stop right here and forgo the frame pack and you will still have an excellent, nigh indestructible bow that will undoubtedly serve you well. This is the point of no return. You have been warned.
Now we begin the process of turning this single piece bow into a three piece take-down bow. PVC take-down bows lose very little draw weight (if any) if made properly, but they do develop a creaking sound when drawn which may be a disadvantage if stealth is desired.
First off, measure 8 1/2 inches from the center on each side of the bow and mark it. Make a mark on either side of the line so that after you cut it you know which piece belongs with which. This will save a lot of headache later. Now cut it off as square as possible. Repeat on the other side.
There should now be three pieces of bow where once there was one whole bow. Don't worry. We're going to put it back together and the first step in that process is filing down the cut edges. File down the edges at an angle so that the inner edge is taller than the outer edge.
Repeat this process for every edge that you just cut.
Step 12: Putting the Bow Back Together
Remember those two 4in. sections of 1in. pipe we cut at the very beginning? These are going to become sleeves that cover the cut edges of the bow and hold it together. Take them and file the edges down so that the outside edge is taller than the inside. This will allow them to slip over the edges of the bow more easily.
Next take the pieces of your bow and mark 2in. from each cut edge.
Next take one of the 4in. pieces and heat up 3/4 of it. You need to get it very flexible while still keeping part of is solid enough to hold onto. Once it heats up enough take it and try to force it over one of the cut ends of the bow. This will not be easy and you will likely have to take the sleeve off and reheat it more than once. Once you've pushed the sleeve to the two inch mark let it cool completely before forcing the matching end of the bow in the other end.
Sight down the bow to make sure it stays straight throughout this process.
After both sleeves cool completely mark them so that you know which bow piece goes into which side and pull them apart.
Take out your PVC primer and cover the section of the bow arm piece that overlaps the sleeve. Do the same with the sleeve. Then cover both sections with PVC cement and put them back together. Repeatfor the other bow arm. DO NOT do this to the handle piece.
Once the glue dries your bow is done.
Now is a good time to paint and/or add a handle wrap. I will be doing both to my bow but this is optional and I will not be including instructions because this instructable is long enough already without me adding more steps.
Step 13: Making Pins
When you make the bow into the frame for a pack it is sometimes helpful to to have small sections of PVC to hold it in place while you lash it together (You can also use rocks).
Take a piece of scrap PVC about 3in. long and cut it in half lengthwise. Heat up the bottom half of the piece and jam it into the handle section. Bend the PVC sticking out upwards and allow it to cool. Then heat up the other half and jam it into the bow arm. Hold the handle and bow arm and bend them so they form a roughly triangular shape (A triangle with one missing side). Repeat for the other side.
When you're done you should have two horribly misshapen chunks of PVC that will hold your bow more or less in place.
Step 14: Impromptu Bowstring
A real bowstring takes time to make (although admittedly not much) and requires materials that are difficult to scavenge unless you happen upon a smoldering archery supply outlet. However, you can make a very serviceable bowstring out of 1/8in. polycord. You could also make a bowstring out of paracord, but since paracord is made out of nylon it will stretch a great deal. The polycord will also stretch, but not nearly as much.
First take a loop of polycord and tie an overhand knot in it to make a loop. Make the loop 3-4in. long. Slide the loop into the nock and stretch the string to the other end. Tie another overhand loop about 5in. below the nock. Now pull the loop over the nock.
Now check the brace (the distance between the string and the handle). You want a brace somewhere between 4 and 6in. Adjust the loops as necessary. Your polycord will stretch some at the beginning which can make your brace smaller.
Step 15: Hammock
Take a double sheet and fold over the top 2in. Sew it to form a loop along the top. Repeat for the bottom of the sheet. Then take 10 of your 20ft. of rope and feed it through one of the loops. Once it is all the way through, tie the two ends together and pull the sheet into a bunch. Repeat the process for the other end and attach it to a tree or pole with a larks head knot. (I would love to show you the hammock in action but there are no trees in my yard and I am banned from my neighbors trees.)
This is not an extravagant hammock. There are many hammocks and many hammock materials that are better than it but this hammock has very little tailoring for a reason. This hammock is meant to be made on the run. Bedsheets are easy to find and when the ropes are removed you are left with a large square of cloth that can be used as a rain shelter (if you waterproof it) a sunshade (if you don't) a shelter from ravening zombies or bears (if hung very high in a tree) or a haversack (when combined with a specially designed PVC recurve bow)
Step 16: Lashing the Bow to Make a Frame
Take the pins you made and insert them into the ends of the bow or prop them against a handy rock. The bow should be in the shape of an isosceles triangle. Tie an overhand knot to hold the siyahs together temporarily and turn your attention to one of the base angles. Take a leather lace (Paracord won't work. The PVC is too slick) and run it over one side and under the other. Wrap it around the top of the frame and pass it under the other frame. Continue making a figure eight with your lace until you run out of length and tie an overhand knot. Repeat for the other side.
For the siyahs wrap a leather lace around the cross until it holds in place and tie it off with an overhand knot. Now you have the frame for your pack.
Step 17: Packing the Sack
Take you hammock and place it on the ground. Fold it in half lengthwise and place what you want to carry in the center. Fold the bottom of the the sheet up. Then fold the left and right sides over. Lastly fold the top half down.
Step 18: Strapping the Sack
Attach two canvas belts to the bottom section of the pack (Any strap will work.) and place your bundle on top. Grab one of the ropes from your hammock and tie it to the center of the handle section of your frame. move the rope up diagonally and wrap it around the sides of the frame about halfway up. Pull it around the back and cross the ropes. Pull the ropes up to the top of the frame where the siyahs cross. Cross the ropes again and wrap them around the siyahs. Tie them together with an overhand knot.
Grab the ropes where they cross right below the siyahs. Pull the top flap of your bundle through this narrow gap. The tension on the ropes will hold the top close, but it also allows you access the contents of your pack even when its on your back.
Step 19: Putting the Frame On
Grab the frame where the siyahs cross. Reach down and lift one of the belts hanging from the bottom of the pack. Grab both the belt and the siyahs in one hand. Grab the other belt and do the same tie both belts together behind the siyahs and you pack is done.
Congratulations. You have just successfully crafted an ergonomic frame pack that can easily be transformed into a serviceable bow and a hammock.
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